Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
  • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
  • H03D7/14—Balanced arrangements
  • H03D7/1408—Balanced arrangements with diodes

Definitions

• the present invention relates to a frequency converter, and particularly to a mixer. Background art
• Patent Document 1 Japanese Patent Application Laid-Open No. 2003-69343 discloses the principle of an even harmonic mixer using an anti-parallel diode.
• COHN, JAMES E. DEGENFORD, BURTON A. NEWMAN “Harmonic Mixing with an Antiparallel Diode Pair” IEEE Transaction on Microwave Theory and Techniques, August 1975, vol.MTT-23, No.8, ⁇ 667673) are known.
• the single-balanced harmonic mixer divides the local oscillation signal Lo into two signals with a phase difference of 180 degrees and the same amplitude by a balanced balun, and gives it to the anti-parallel diode.
• the anti-parallel diode is also supplied with a high-frequency reception signal RF. Then, the local oscillation signal Lo and the high-frequency reception signal RF are mixed by the anti-parallel diode, and the intermediate frequency signal IF is obtained. If the frequency of the intermediate frequency signal IF is f IF, the frequency of the local oscillation signal Lo is f Lo and the frequency of the high-frequency reception signal RF is f RF,
• the single-balanced harmonic mixer has the advantage that the local oscillation signal Lo and its harmonics do not leak to the input side of the high-frequency reception signal RF.
• the impedance of the output terminal of the balanced balun is the impedance of the terminal of the anti-parallel diode connected to the balanced balun.
• the balanced balun is designed to correspond to the band of f Lo, and it is difficult to design it to correspond to the band of f RF. Then, the impedance of the output terminal of the balance balun fluctuates greatly.
• an object of the present invention is to make the frequency characteristics of conversion loss when converting a high-frequency reception signal into an intermediate frequency signal substantially constant.
• a signal branching unit that branches a local oscillation signal into two signals, a constant impedance element through which the two signals pass, an output of the constant impedance element, and a high-frequency reception signal And a mixing means for generating an intermediate frequency signal by mixing the high frequency reception signal and the constant impedance element in the frequency band of the high frequency reception signal. It is configured to have a sense.
• the signal branching unit branches the local oscillation signal into two signals. Two signals pass through the constant impedance element.
• the mixing means mixes the output of the constant impedance element and the high frequency received signal to generate an intermediate frequency signal.
• the constant impedance element has a substantially constant impedance in the frequency band of the high-frequency reception signal.
• the two signals can be two signals having the same amplitude and different phases by 180 degrees.
• the impedance of the constant impedance element can be set to almost 0 ⁇ in almost the entire frequency band of the high-frequency reception signal.
• the constant impedance element makes it easier to pass a signal having a frequency within the frequency band of the two signals than a signal within the frequency band of the high-frequency reception signal. Can be.
• the constant impedance element can be a low-pass filter whose cutoff frequency is the upper limit of the frequency band of the two signals.
• the constant impedance element includes a band-pass filter having a pass band of the frequency band of the two signals. can do.
• the constant impedance element can be a diplexer having a pass band in a signal frequency band and exhibiting termination characteristics in a frequency band of a high-frequency received signal.
• the signal branching unit can be a balanced balun corresponding to the frequency band of the local oscillation signal.
• the mixing means connects the anode to one of the diodes and the cathode of the one of the diodes, and connects the cathode to the anode of the one of the diodes.
• the other diode to which one diode is connected, the first terminal to which the cathode of one diode is connected to the anode of the other diode, the cathode of the other diode and the anode of one diode are connected.
• a second terminal connected thereto.
• the first terminal receives the output of the constant impedance element, the second terminal receives a high frequency reception signal, and the second terminal outputs an intermediate frequency signal. It can be configured as follows.
• the high frequency input terminal connected to the second terminal and receiving the input of the high frequency reception signal, and the signal in the frequency band of the intermediate frequency signal connected to the second terminal And an intermediate frequency signal output terminal connected to the intermediate frequency band filter.
• FIG. 1 is a circuit diagram showing a configuration of the frequency converter 1 according to the first embodiment of the present invention.
• FIG. 2 is a graph showing impedance characteristics of low-pass filter elements (constant impedance elements) 12a and 12b.
• FIG. 3 is a diagram showing an example of a circuit configuration of the mouth-to-pass filter 12a and 12b.
• FIG. 4 is an impedance chart showing an example of the impedance characteristics of the mouth-to-pass filter 12a and 12b.
• FIG. 5 is a circuit diagram showing a configuration of the frequency converter 1 according to the second embodiment of the present invention.
• FIG. 6 is a graph showing the impedance characteristics of diplexers (constant impedance elements) 22a and 22b.
• FIG. 7 is a circuit diagram showing an example of a circuit configuration of the diplexers 22a and 22b.
• FIG. 1 is a circuit diagram showing a configuration of the frequency converter 1 according to the first embodiment of the present invention.
• Frequency converter 1 is a local oscillation signal input pin 10 a, balanced balun (signal branching means) 10, low-pass fill element (constant impedance element) 12a, 12b, coil for DC return 14a, 14b, anti-parallel diode (mixing means) 1 6a, 16b, anti-parallel diode connection point 17, and RF / IF signal separation unit 18 are provided.
• the frequency converter 1 extracts the intermediate frequency signal IF by mixing the local oscillation signal Lo and the high-frequency reception signal RF.
• the local oscillation signal input terminal 10a is a terminal that receives the input of the local oscillation signal Lo (frequency f Lo).
• the local oscillation signal Lo input to the local oscillation signal input terminal 10 a is given to the balanced balun 10.
• the frequency f Lo is, for example, 4 to 8 GHz.
• the balanced balun (signal branching means) 10 branches the local oscillation signal Lo into two signals having the same amplitude and different phases by 180 degrees. The frequencies of the two signals are the same as the frequency of the local oscillation signal Lo. If the phase of one signal is 0 °, the phase of the other signal is 180 ° (see Figure 1).
• the balanced balun 10 is designed to correspond to the frequency band of the local oscillation signal Lo (for example, 4 to 8 GHz).
• One-pass filter (constant impedance element) 1 2a receives one signal output from balanced balun 10.
• Low-pass filter (constant impedance element) 1 2b receives the other signal output from balanced balun 10.
• the low-pass filters 12 a and 12 b are low-pass filters whose cut-off frequency is the upper limit of the frequency band of the signal output from the balanced balun 10. Note that the frequency band of the signal output from the balanced balun 10 is the same as the frequency band of the local oscillation signal Lo.
• the upper limit of the frequency band of the signal output by the balanced balun 10 is 8 GHz, and the cutoff frequency is 8 GHz.
• a signal having a frequency equal to or lower than the cut-off frequency (a signal output from the balance balun 10) is converted from a signal having a frequency exceeding the cut-off frequency (eg, a signal within a frequency band of the high-frequency reception signal RF). Let them pass well.
• the impedance characteristics of the one-pass filter (constant impedance elements) 12a and 12b will be described with reference to the graph in FIG.
• the impedance of the low-pass filter 12a and 12b is almost constant in the frequency band of the high-frequency reception signal RF (for example, 9 to 49 GHz). Specifically, it is 50 ⁇ at 8 GHz, but it rapidly approaches 0 ⁇ (for example, much smaller than 50 ⁇ at 9 GHz) as the frequency increases, and eventually becomes 0 ⁇ . That is, it is almost 0 ⁇ in almost the entire frequency band of the high-frequency reception signal RF.
• Fig. 3 shows an example of the circuit configuration of the low-pass filter 12a and 12b.
• the low-pass filters 12a and 12b are composed of a reactance element L and a reactance element L, one end of which is connected to the balanced balun 10 and the other end of which is connected to the anti-parallel diodes 16a and 16b. It has a capacitance element C connected to one end and grounded, and a capacitance element C connected to the other end of the reactance element L and grounded.
• Fig. 4 shows the impedance chart (Smith chart) of the mouth-to-pass fills 12a and 12b configured as shown in Fig. 3. See Fig. 4.
• the impedance is 50 ⁇ at a frequency of 8 GHz, but the impedance sharply decreases at frequencies of 9 to 10 GHz, and approaches 0 ⁇ at a frequency of 20 GHz.
• the DC return coil 14a is a coil whose one end is connected to the output side (opposite to the balanced balun 10) of the mouth-to-pass filter 12a and the other end is grounded.
• One end of the DC return coil 14b is connected to the output side of the low-pass filter 12b (opposite to the balanced balun 10), and the other end is grounded.
• a DC power supply for supplying a desired DC voltage to the anti-parallel diodes 16a and 16b may be connected.
• the anti-parallel diode (mixing means) 16a has diodes 162a and 1664a, a first terminal 166a, and a second terminal 168a.
• the diode 162a has an anode connected to the RF / IF signal separation section 18 and a power source connected to the mouth-to-pass filter 12a.
• Diode 164a is a diode in which the anode is connected to the force sword of diode 162a and the cathode is connected to the anode of diode 162a.
• the first terminal 166a is a terminal to which the force source of the diode 162a and the anode of the diode 164a are connected.
• the second terminal 168a is a terminal to which the cathode of the diode 164a and the node of the diode 162a are connected.
• the output of the low-pass filter 12a is input to the first terminal 16a.
• the high frequency reception signal RF is input to the second terminal 168a.
• An intermediate frequency signal IF is output from the second terminal 168a.
• the anti-parallel diode (mixing means) 16b has a diode 162b, 164b, a first terminal 1666b, and a second terminal 1668b.
• the diode 16 2 b has an anode connected to the RF / IF signal separation section 18 and a power source connected to the mouth-to-pass filter 12 b.
• Diode 1664b is a diode in which the anode is connected to the force node of diode 162b and the cathode is connected to the node of diode 162b.
• the first terminal 166b is a terminal to which the cathode of the diode 162b and the anode of the diode 164b are connected.
• the second terminal 1668b is a terminal to which the force source of the diode 1664b and the anode of the diode 1662b are connected.
• the output of the low-pass filter 12 b is input to the first terminal 16 b.
• the high frequency reception signal RF is input to the second terminal 168b.
• An intermediate frequency signal IF is output from the second terminal 168b.
• the anti-parallel diode connection point 1 ⁇ ⁇ is a connection point where the second terminals 168 a and 168 b are connected to the R FZIF signal separation unit 18.
• the RF / IF signal separation section 18 receives the high-frequency reception signal RF and outputs it to the second terminals 168a and 168b. Then, the intermediate frequency signal IF is received from the second terminals 168a and 168b, and the intermediate frequency signal IF is extracted.
• the RF / IF signal separation section 18 has a high frequency band filter 18 2, a high frequency input terminal 18 2 a, an intermediate frequency band filter 18 4, and an intermediate frequency signal terminal 18 4 a.
• the high-frequency band filter 182 is connected to the second terminals 168a and 168b.
• the high-frequency band filter 18 2 is a filter that passes a signal in the frequency band (for example, 9 to 49 GHz) of the high-frequency reception signal RF.
• the signal having the frequency f IF (for example, 1 GHz) of the intermediate frequency signal IF is more difficult to pass (preferably cut off) than the signal in the frequency band of the high-frequency reception signal RF.
• the high frequency input terminal 182a is connected to the second terminals 168a and 168b via the high frequency band filter 182.
• the high frequency input terminal 18 2 a receives the input of the high frequency reception signal RF.
• the intermediate frequency band filter 184 is connected to the second terminals 168a and 168b.
• the intermediate frequency band filter 184 is a filter that passes a signal of the intermediate frequency signal IF having a frequency fIF (for example, 1 GHz).
• a signal in the frequency band of the high-frequency reception signal RF (for example, 9 to 49 GHz) is harder to pass (preferably cut off) than a signal of the intermediate frequency signal IF of frequency f IF (for example, 1 GHz).
• the intermediate frequency signal output terminal 184a is connected to the second terminals 168a and 168b via the intermediate frequency band filter 184.
• the intermediate frequency signal output terminal 184a is a terminal to which the intermediate frequency signal IF is output.
• Local oscillation signal Lo (frequency fLo) is input to local oscillation signal input pin 10a.
• the frequency f Lo is, for example, 4 to 8 GHz.
• the local oscillation signal Lo is split by the balanced balun 10 into two signals having the same amplitude and 180 degrees out of phase. These two signals pass through the low-pass filters 12a and 12b, and are supplied to the first terminals 16a and 16b of the anti-parallel diodes 16a and 16a.
• the high frequency reception signal RF (frequency f RF) is input to the high frequency input terminal 182a of the RF / IF signal separation section 18.
• the high-frequency reception signal RF passes through the high-frequency band filter 182 and is given to the second terminals 168a and 168b.
• the anti-parallel diodes 16a and 16b convert the even harmonics of the two signals (frequency fLo) passing through the low-pass filters 12a and 12b and the high-frequency reception signal RF (frequency fRF). Mix.
• an intermediate frequency signal IF (frequency f IF) is obtained.
• IF frequency f IF
• N is a positive integer (1, 2, 3, ).
• the frequency f IF 1 GHz. That is,
• the even harmonic 2 N ⁇ f Lo (N is a positive integer) is the second terminal 16 8 cancel each other out at a (16 8 b). Therefore, the harmonic of the local oscillation signal Lo does not leak to the high frequency input terminal 18a.
• the anti-parallel diodes 16 a (16 b) are opposite to each other regardless of the phase of the local oscillation signal Lo fed. Either a, 16a (162b, 164b) can be regarded as the ON state.
• the impedance seen from the anti-parallel diode connection point 17 to the anti-parallel diode 16a (16b) almost coincides with the input / output impedance of the low-pass filter 12a (12b). I do.
• the input-output impedance of the single-pass filter 12a (12b) is almost constant in the frequency band (for example, 9 to 49 GHz) of the high-frequency reception signal RF as described above. Therefore, the frequency characteristics of the conversion loss when converting the high-frequency reception signal RF into the intermediate frequency signal IF are almost constant even if the frequency f RF of the high-frequency reception signal RF fluctuates.
• the impedance seen from the anti-parallel diode connection point 17 to the anti-parallel diode 16 a (16 b) is almost balanced. Matches the balun 10 imbi dance.
• the impedance of the balanced balun 10 fluctuates greatly in the frequency band of the high-frequency received signal RF. Therefore, the frequency characteristics of the conversion loss when converting the high-frequency reception signal RF into the intermediate frequency signal IF fluctuate greatly when the frequency f RF of the high-frequency reception signal RF fluctuates.
• the mixing efficiency is improved. Therefore, the impedance (port) from the input end of the high-frequency reception signal RF (the anti-parallel diode connection point 17) via the non-linear elements (the anti-parallel diodes 16 a and 16 b)
• the impedance of the one-pass filter (12a, 12b) is almost 0 ⁇ in almost the entire frequency band of the high-frequency reception signal RF. Therefore, the efficiency in converting the high-frequency reception signal RF to the intermediate frequency signal IF is high. Is improved and the loss is low.
• the intermediate frequency signal IF generated by the anti-parallel diodes 16a and 16b is supplied to an RF / IF signal separation unit 18.
• the intermediate frequency signal IF cannot pass through the high frequency band filter 182, but passes through the intermediate frequency band filter 184. Therefore, the intermediate frequency signal IF is output from the intermediate frequency signal output terminal 1884a. Since the high-frequency reception signal RF passed through the high-frequency band filter 18 2 cannot pass through the intermediate frequency band filter 18 4, the signal obtained from the intermediate frequency signal output terminal 18 4 a includes the high-frequency reception signal RF. No RF mixing.
• the input / output impedance of the low-pass filter 12a (12b) is substantially constant in the frequency band of the high-frequency reception signal RF (for example, 9 to 49 GHz). Therefore, the frequency characteristics of the conversion loss when converting the high-frequency reception signal RF into the intermediate frequency signal IF are almost constant even if the frequency f RF of the high-frequency reception signal RF fluctuates. However, the efficiency in converting the high-frequency reception signal RF into the intermediate frequency signal IF is improved, and the loss is low.
• a band-pass filter (impedance characteristic is a single-band) whose pass band is the frequency band (for example, 4 to 8 GHz) of the signal output from the balanced balun 10 is used.
• the same effect can be obtained by using the same as for the pathfills 12a and 12b (see Fig. 2).
• FIG. 5 is a circuit diagram showing a configuration of the frequency converter 1 according to the second embodiment of the present invention.
• the frequency converter 1 has a local oscillation signal input terminal 10a, a balanced balun (signal branching means) 10, a diplexer (constant impedance element) 22a and 22b, a DC return coil 14a and 14b, an anti-parallel diode ( Mixing means) 16a, 16b, antiparallel diode connection point 17, and RF / IF signal separation unit 18 are provided.
• Local oscillation signal input terminal 10a balanced balun (signal branching means) 10, DC return coils 14a, 14b, anti-parallel diode (mixing means) 16a, 16b, anti-parallel diode connection point 17,
• the RF / IF signal separation unit 18 is the same as in the first embodiment, and the description is omitted.
• the diplexers (constant impedance elements) 22 a and 22 b use the frequency band (for example, 4 to 8 GHz) of the signal output from the balanced balun 10 as a pass band, and the frequency band of the high-frequency reception signal RF (for example, 9 to 49 GHz). ) Shows termination characteristics (having characteristics as a terminator).
• the impedance characteristics of the diplexers (constant impedance elements) 22a and 22b will be described with reference to the graph of FIG.
• the impedance of the diplexer (constant impedance element) 22 a and 22 b is almost constant 50 ⁇ in the frequency band of the high-frequency reception signal RF (for example, 9 to 49 GHz).
• Fig. 7 shows an example of the circuit configuration of the diplexers 22a and 22b.
• Fig. 7 (a) shows an example in which diplexers 22a and 22b are configured using bandpass filters.
• the diplexers 22a and 22b are connected to the balanced balun 10 at one end and the antiparallel diodes 16a and 16b at the other end.
• a resistor 222 connected to the bandpass filter 222 and grounded.
• the bandpass filter 222 is the passband of the frequency band (eg, 4 to 8 GHz) of the signal output by the balanced balun 10.
• the bandpass filter 222 passes the frequency band of the high-frequency reception signal RF (for example, 9 to 49 GHz).
• FIG. 7 (a) shows an example in which diplexers 22a and 22b are configured using bandpass filters.
• the diplexers 22a and 22b are connected to the balanced balun 10 at one end and the antiparallel diodes 16a and 16b at the other end.
• diplexers 22a and 22b are configured using LCRs of circuit elements.
• the diplexers 22a and 22b are connected to one end of the balance balun 10 and one end of the reactance element L having one end connected to the anti-parallel diodes 16a and 16b, and one end of the reactance element L.
• the grounded capacitance element C 2 and the reactance element It has a capacitance element C1 connected to the other end, and a resistance element R1 connected to the capacitance element C1 and grounded.
• the operation of the second embodiment is almost the same as that of the first embodiment. Note that the anti-parallel diodes 16a (16b) are opposite to each other regardless of the phase of the local oscillation signal Lo supplied.
• the impedance seen from the anti-parallel diode connection point 17 to the anti-parallel diode 16a (16b) almost matches the input / output impedance of the diplexer 22a (22b).
• the input / output impedance of the diplexer 22a (22b) is almost constant in the frequency band of the high-frequency reception signal RF (for example, 9 to 49GHz). Therefore, the frequency characteristic of the conversion loss when converting the high-frequency reception signal RF into the intermediate frequency signal IF is almost constant even if the frequency of the high-frequency reception signal RF: f RF fluctuates.
• the input and output impedances of the diplexers 22a and 22b are substantially constant in the frequency band of the high-frequency reception signal RF (for example, 9 to 49 GHz). Therefore, the frequency characteristic of the conversion loss when converting the high-frequency reception signal RF into the intermediate frequency signal IF is almost constant even if the frequency f RF of the high-frequency reception signal RF fluctuates.

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• Power Engineering (AREA)
• Superheterodyne Receivers (AREA)

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• 2004
  • 2004-12-16 JP JP2005516620A patent/JPWO2005064787A1/ja active Pending
  • 2004-12-16 US US10/596,790 patent/US20070099590A1/en not_active Abandoned
  • 2004-12-16 DE DE112004002557T patent/DE112004002557T5/de not_active Withdrawn
  • 2004-12-16 WO PCT/JP2004/019269 patent/WO2005064787A1/ja active Application Filing

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